1. Field of Invention:
This invention relates generally to telephony, specifically to a combined handset and headset for a telephone.
2. Description of Prior Art:
In the 1930s telephone sets of the "candlestick" variety were widely used. They comprised an elongated, upright housing with a dial at the bottom and a funnel-like microphone at the top, together with a separate earpiece which contained a speaker. The earpiece, the upright housing, and a wall-mounted control box were connected by wires. Users found this set awkward because they usually had to hold (a) the microphone housing in one hand so that its microphone was close to the mouth, and (b) the earpiece against the ear with the other hand. Users could leave the microphone housing on a desk or table, but in this case they had to bring their heads close to the microphone while holding the earpiece against an ear.
This type of telephone was replaced by one in common household use today. This set has a dial in one housing and the microphone and speaker at respective ends of another, elongated handheld housing, termed a handset. This type of telephone allowed the user to hold just one housing for speaking and listening--the handset--with one hand and still be able to move about with one hand free. Thus it was a great improvement on the former candlestick set. However it was not well suited for stockbrokers, telephone operators, receptionists, and other users who had to remain on the phone for long periods of time. This is because while users were speaking or listening on the line, they had to hold the handset so that its speaker was continuously against an ear and its microphone was continuously close to the mouth. As this tired users physically and left only one hand free for other tasks, they felt a need for a "hands-free" handset, or headset.
Several types of headsets thus came into use, but these had various disadvantages.
In one, the speaker was held to the head by an over-the-head clamp or band while the micrphone was connected to the speaker by an arm or boom which placed it in front of the user's mouth. While suitable for use as a headset, users found it awkward to hold the headset by hand, as they would want to do for intermittent use. This is because it took more effort to install on the head than was justified by a brief use. While it could be held in the user's hand and used like a handset, it was awkward and difficult to use in this manner because of its relatively complex shape, principally because its headband interfered with use.
Another type of headset is shown in U.S. Pat. Nos. 3,280,273 to Flygstad et al. (1966), 3,610,841 to Hutchings (1971), 4,335,281 to Scott et al. (1982), and 4,273,969 to Foley et al. (1981). These sets had housings which fit behind the auricle or pinna (external part of the ear) and a flexible eartube speaker which extended around and forward from the post-pinna housing, or back from a fore-pinna part of the housing, into the auditory canal. While these devices eliminated the need for a headband by clamping or holding the pinna between the housing and the eartube, they could not be used as a handset because their curved eartubes could not be placed in the ear canal unless the device were fully installed on the user's head. This involved putting the housing on the pinna and then inserting the flexible tube into the auditory canal, an awkward operation. In addition, for sanitary reasons, the eartube made the set suitable for use only by a single user. Finally, they had poor positional stability; this caused the location of the microphone to vary so that it was not always in front of the mouth. Designers solved this problem by providing an adjustable microphone boom, but the whole set was still unstable becuase it was held in place simply by gravity. Also the boom had to be adjusted frequently, depending on the current orientation of the set on the head. Omni-directional microphones could solve this problem somewhat, but they had poor signal-to-noise ratios since they picked up ambient noise.
U.S. Pat. No. 2,474,135 to White (1949) shows an earpiece (no microphone attached) which contains a speaker housing which is positioned adjacent the ear canal and a curved part which is hinged to the speaker housing so that it can be pivoted behind the ear to clamp the pinna between the curved part and the speaker. U.S. Pat. No. 3,862,378 to Norris (1975) made use of White's arrangement for headsets by extending a microphone boom from the speaker housing. However this headset could not conveniently be used as a handset because of interference from the curved part when the speaker housing was held against the ear. Also it was somewhat awkward to install on an ear because its curved parts had to be pivoted away from its speaker housings and then released or pivoted back. Further, Norris's device had a fixed spacing between its pivot and the speaker housing so that it was suitable for one size of pinna only; users with very large or very small pinnas could not wear the device comfortably or stably. Finally it was suitable for the ear on a predetermined side of the head only.
Enokido, in U.S. Pat. No. 4,453,050 (1984) showed an earphone which could be adjusted for varying pinna sizes, and could be used on either side of the head. However it had to be manually adjusted for the ear side and for the pinna size, the latter in a trial-and-error operation, which was awkward and time consuming.